Conventionally, a method for converting data has been known that uses a table such as an LUT (Look Up Table) representing the relationship between input and output, namely, between data before conversion and data after conversion.
For example, an image-processing apparatus such as s color ink-jet printer first compresses a conversion table in which color components constituting image data are arranged, and stores it as a compressed inversion table. Then, when restoring the data, the image-processing apparatus expands the compressed conversion table, and executes interpolation based on the expanded compressed conversion table to convert the input image data. As such, the method has been known that makes the data volume of a table to be stored smaller (see, for example, Patent document 1).
In addition, in order to convert input image data into output image data in a color correction process that uses a color correction table, an image processing apparatus compresses the color correction table, and stores it in a fixed way, and when executing conversion, expands the color correction table and executes the color correction. As such, the method has been known that makes the data volume of a table to be stored smaller (see, for example, Patent document 2).
As another case, in image processing, an image processing apparatus first compresses image data and LUT data according to a predetermined compression scheme, and stores them in the memory. In addition, the image processing apparatus has a DMA (Direct Memory Access) controller that transmits the compressed LUT data read out of the memory to an expansion part to expand the data, and a memory to store the expanded LUT data. With such a configuration, a method has been known that works on the configuration in which a dedicated unit for expanding the LUT data is omitted (see, for example, Patent document 3).